Thrust reverser with turning vanes capable of being superposed

ABSTRACT

A thrust reverser for a turbofan jet engine having a stationary structure defining an upstream part of a fan cowling and an axially displaceable, annular structure located downstream of the stationary structure, wherein the inner surface of the fan cowling is spaced from an outer surface of an engine cowling to form an annular duct. A plurality of flaps form a portion of the inner surface of the fan cowling during a forward thrust position, and in a reverse thrust position, the flaps pivotably rotate about a stationary pivot so that their first edges are adjacent with the outer surface of the engine cowling to block the annular duct. A plurality of thrust reverser baffle portions are covered by the flaps during the forward thrust position, and during the reverse thrust position, the thrust reverser baffle portions cover a passageway in the fan cowling between the stationary structure and the displaceable structure. The plurality of thrust reverser baffle portions are radially offset and substantially parallel, and comprise a stationary baffle portion and at least one movable baffle portion. In a reverse thrust position, the movable baffle portions are displaced so that the plurality of thrust reverser baffles are longitudinally juxtaposed, redirecting the deflected gas flow.

This is a 371 of PCT/FR99/02904 filed Nov. 25, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thrust reverser for a bypassturbojet-engine, and more particularly, a thrust reverser havingrotatable pivoting flaps closing an annular gas flow duct and stationarybaffle portions radially offset with movable baffle portions redirectinga gas flow.

2. Related Art

Turbofan-type turbojet engines typically comprise a turbojet engineencased in a cowling wherein the engine drives a fan usually located atthe front portion of the engine. The fan blades are enclosed in a fancowling so that at least a portion of the is fan cowling is spaced fromthe engine cowling to define a generally annular gas flow duct. Theannular gas flow duct channels the air impelled by the rotation of thefans.

As shown in FIGS. 1 and 2, it is known to position a thrust reverser soas to act against the gases flowing through the annular duct. FIG. 1illustrates a thrust reverser in a forward thrust position having adisplaceable structure (7) with an inner surface spaced from an outersurface (16) of an engine cowling so as to form an annular gas flow duct(17). In the forward thrust position, a flap (12) covers a plurality ofthrust reverser baffles (20) housed within the displaceable structure(7) by forming a portion of the inner surface of the displaceablestructure (7). FIG. 2 illustrates the thrust reverser in FIG. 1 in areverse thrust position wherein the displaceable structure (7) isaxially displaced downstream to clear a passageway in the fan cowlingfor the flow deflected between the stationary structure (6) and anupstream edge of the displaceable structure (7). The flap (12) rotatesso that one edge is adjacent with the outer surface (16) of the enginecowling to block the annular duct (17) and the flow is outwardlydeflected from the passageway by the thrust reverser baffles (20).

European patent 0,109,219 A and U.S. Pat. No. 3,500,645 disclose typicaldesigns using thrust reverser baffles. In these instances, baffles arerigidly connected to a non-translatable part of the fan cowling so thatin a reverse thrust mode, a pivotable flap redirects the gas in theannular duct and the baffles effectively divert the exhausted gasthrough a passageway in the fan cowling. However, in such designs, theintegration of thrust reverser baffles dictate the length of thedisplaceable structure which may increase the weight and requireincreased storage space in the jet engine cowling.

SUMMARY OF THE INVENTION

A thrust reverser is disclosed for a turbofan jet engine having astationary structure defining an upstream part of a fan cowling and anaxially displaceable, annular structure located downstream of thestationary structure. The displaceable structure forms a downstreamexternal part of the fan cowling and a downstream part of a radial innersurface spaced from an outer surface of an engine cowling so as to forman annular gas flow duct. During a reverse thrust position, thedisplaceable structure is axially displaced to the rear to clear apassageway in the fan cowling for the flow deflected between thestationary structure and an upstream edge of the displaceable structure.A plurality of flaps form a portion of the inner surface of thedisplaceable structure during a forward thrust position, and in reversethrust position, the flaps pivotably rotate about a stationary pivot sothat their first edges are adjacent to the outer surface of the enginecowling effectively blocking the gas flow in the annular duct. Aplurality of thrust reverser baffle portions are supported by thestationary structure and are covered by the flaps during the forwardthrust position, and during the reverse thrust position, the thrustreverser baffle portions are within the passageway such that the thrustreverser baffle portions redirect the gas flow deflected by the flaps ina reverse thrust direction.

A turbofan thrust reverser according to the invention enables efficientforward and reverse thrust performances without incurring the drawbacksof the known designs. The plurality of thrust reverser baffle portionscomprise two types: a stationary baffles portion and at least onemovable baffle portion. The plurality of thrust reverser baffle portionsare radially offset and substantially parallel in both the forward andreverse thrust positions. The stationary baffle portion is connected bya first end to the stationary structure and a second end is locateddownstream the stationary structure. The at least one movable baffleportion is movable with respect to the stationary baffle portion, and inthe reverse thrust position, the at least one moveable baffle portion isdisplaced downstream so that the plurality of baffle portions arelongitudinally juxtaposed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial, longitudinal, cross-sectional view illustrating athrust reverser with a rigidly mounted flow deflecting baffle in theforward thrust position;

FIG. 2 is a partial, longitudinal, cross-sectional view illustrating athrust reverser with a rigidly mounted flow deflecting baffle in thereverse thrust position; FIG. 3 is a partial, longitudinal,cross-sectional view illustrating a thrust reverser with a plurality offlow deflecting baffles in the forward thrust position;

FIG. 4 is a partial, longitudinal, cross-sectional view illustrating athrust reverser with a plurality of flow deflecting baffles in thereverse thrust position; and

FIG. 5 is a further partial, longitudinal cross-sectional viewillustrating another thrust reverser with a plurality of flow deflectingbaffles in the forward thrust position.

Other features and advantages of the invention are elucidated in thefollowing description of an illustrative embodiment of the invention andin relation to the attached drawings.

FIG. 1 is a semi-schematic view, in longitudinal section and in a planepassing through the axis of rotation of a pertinent turbojet-engine, ofa vane-cascade thrust reverser in the closed position, of a known typeand already discussed above,

FIG. 2 is a semi-schematic sectional view similar to that of FIG. 1 ofthe thrust reverser shown in FIG. 1 in the thrust-reversal mode,

FIG. 3 shows a semi-schematic view similar to that of FIG. 1 of a thrustreverser of the invention in the closed position, and

FIG. 4 shows a semi-schematic view similar to that of FIG. 2 of thethrust reverser shown in FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In the embodiment illustrated in FIGS. 3 and 4, the principal differencefrom Figs. l0 1 and 2 is that there is a plurality of thrust reverserbaffle portions (20). The plurality of flow deflecting baffles comprisetwo portions: stationary baffle portion (21) and at least one movablebaffle portion (22). Two movable baffle portions are illustrated as anexample. In both the forward and reverse thrust positions, thestationary baffle portion (21) and the movable baffle portions (22) aresubstantially parallel to one another. The 1 5 stationary baffle portion(21) has a first end rigidly connected to an upstream edge of thestationary structure (6), whereas the movable baffle portions (22) areaxially movable by a displacement mechanism (4). The displacementmechanism (4) comprises a linear actuator that has, in known fashion, anextendible and retractable rod attached to the displaceable structure(7).

When in a forward thrust position, illustrated in FIG. 3, the stationarybaffle portion (21) and the at least one movable are housed within thedisplaceable structure (7) whereat the movable baffle portions (22) areradially below or inward the stationary baffle portion (21). When movingto the reverse thrust position from the forward position, illustrated inFIG. 4, the displacement mechanism (4) axially displaces the 25displaceable structure (7) downstream while also moving each movablebaffle portion (22) downstream so that the plurality of flow deflectingbaffles (20) are longitudinally juxtaposed. The displacement of the atleast one movable baffle portion (22) in connection with the stationarybaffle portion (21) is configured so that the passageway is covered bythe plurality of baffle portions. As the annular duct (16) is blocked bythe flap (12) in the reverse thrust mode, the gas flow (5) is deflectedand redirected by the plurality of baffles (20).

Although the thrust reverser is illustrated in FIGS. 3 and 4 ascomprising two movable baffle portions radially offset with respect tothe stationary baffle portion and with one another, the number ofmovable baffle portions may vary in accordance with each particularapplication on a specific aircraft. Variations of the disclosedembodiment are also possible without departing from the scope of theinvention. For instance, as shown in FIG. 5, the movable baffle portions(22) may be located radially outward from the stationary baffle portion(21).

We claim:
 1. A thrust reverser for a bypass turbojet-engine comprising:a stationary structure defining an upstream part of a fan cowling; anaxially displaceable, annular structure (7) located downstream of thestationary structure which forms a downstream external part of the fancowling and a downstream part of a radial inner surface spaced from anouter surface of an engine cowling (16) therebetween so as to form anannular gas flow duct (17); a plurality of flaps (12) having a firstedges and forming a portion of the inner surface of the displaceablestructure (7) during a forward thrust position and a reverse thrustposition wherein the flaps (12) pivotably rotate about a stationarypivot (15) wherein the first edges are connected to the outer surface ofthe engine cowling (16) so as to deflect a gas flow in the annular duct;a plurality cascade portions (20) supported by stationary structure (6)and covered by the flaps (12) during a forward thrust position and areverse thrust position wherein the cascade portions are located betweenthe movable cowling (7) and the stationary structure (6) such that thecascade portions redirect the gas flow deflected by the flaps into areverse thrust direction; a stationary cascade portion (21) having asecond edge rigidly connected to the stationary structure (6) and afirst end downstream the stationary structure (6); and at least onemovable cascade portion (22) having a second end and a movable withrespect to the stationary cascade portion (21) between a forward thrustposition wherein the second end is adjacent to the first end ofstationary cascade portion (21) and a reverse thrust position whereinthe second end is displaced downstream from the first end so that theplurality of cascade portions are radially offset and longitudinallyjuxtaposed, the at least one movable cascade portion locatedsubstantially parallel to the stationary cascade portion in both theforward and reverse thrust positions.
 2. The thrust reverser of claim 1further comprising a movement mechanism connected on the stationarystructure (6) and the displaceable structure (7) for moving thedisplaceable structure (7), the at least one movable cascade portion(22) and the flaps (12) between the forward and reverse thrustpositions.
 3. The thrust reverser of claim 2 wherein the movementmechanism comprises an actuating cylinder having an extendible and aretractable rod.
 4. The thrust reverser of claim 1 wherein the at leastone movable cascade portion (22) is located radially below thestationary cascade portion (21) in the forward thrust position.
 5. Thethrust reverser of claim 1 wherein the at least one movable cascadeportion (22) is located radially above the stationary cascade portion(21) in the forward thrust position.